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Frequently Asked Questions

Why does Ontology::from_file fail?

Ontology::from_file on ontologos-core intentionally returns Error::ParseNotAvailable to keep the core crate free of parser dependencies.

Load OWL/RDF files with ontologos-parser:

use ontologos_parser::load_ontology;

let ontology = load_ontology(path::Path::new("ontology.owl"))?;

Or use the CLI: ontologos profile ontology.owl

See Load an OWL file.

Which crate should I depend on?

For v0.5, typical workflows use:

[dependencies]
ontologos-core = "0.5.0"
ontologos-parser = "0.5.0"   # OWL/RDF file loading
ontologos-profile = "0.5.0"  # EL / RL / QL / DL detection
ontologos-rdfs = "0.5.0"     # RDFS materialization
ontologos-rl = "0.5.0"       # OWL RL saturation

Depend on ontologos-core only if you build ontologies programmatically or from JSON snapshots.

There is no umbrella ontologos crate on crates.io. The CLI binary is built from ontologos-cli in this repository.

Can I use OntoLogos instead of Protégé + HermiT today?

Not for full OWL DL classification. v0.5 loads OWL files, detects profiles, materializes RDFS TBox inferences, saturates OWL RL ontologies, and classifies OWL EL taxonomies via ontologos-el. CLI classify --profile auto|el|rl|rdfs routes to the correct engine. Use Protégé with HermiT or Konclude for production OWL DL workflows.

OntoLogos is for early adopters who want to embed the Rust data model, load ontologies natively, run RL saturation, or follow the roadmap.

Why was my JSON rejected?

Common causes:

  • format_version: 1 — v1 is rejected for untrusted input; use JSON v2
  • Invalid IRI — only http, https, and urn schemes; no control characters
  • Unknown entity IRI in axioms — declare all entities before referencing them in axioms
  • Size limits — default max JSON size is 16 MiB; see Security

Why does Pizza detect as DL?

Profile classification uses mapped TBox shapes (parse_meta.profile_constructs). The Pizza corpus mixes EL shapes (existentials) with constructs that rule out EL and RL (e.g. inverse and functional object properties), so detection reports DL. Diagnostics explain which mapped constructs violate EL/RL profile rules and may also list constructs seen in the source but not stored in core (e.g. ObjectAllValuesFrom).

See Profile detection.

Why doesn't ontology.axiom_count() match Protégé's axiom count?

The parser maps a subset of OWL constructs into the core model. Complex class expressions, many data-property axioms, and some property axioms are scanned for profile detection but skipped during mapping. Named ABox axioms (ClassAssertion, ObjectPropertyAssertion, SameIndividual, DifferentIndividuals) are mapped in v0.4. axiom_count() is mapper output, not raw OWL logical axiom count.

See Protégé vs OntoLogos counts, Troubleshooting, and Supported constructs.

What is the difference between ROADMAP.md and PLAN.md?

ROADMAP.md on GitHub is the canonical semver release plan. PLAN.md on GitHub is historical background and ecosystem vision; prefer ROADMAP for current status.

Is OntoLogos the same as Ontologos?

Display name: OntoLogos. Crate and command names: ontologos-* and ontologos (lowercase).

How do I load the pizza test fixture?

From JSON (no download):

let json = include_str!("../tests/fixtures/pizza_minimal.json");
let ontology = Ontology::from_json(json)?;

From OWL (benchmark corpus):

./benchmarks/scripts/download.sh

let ontology = ontologos_parser::load_ontology(path::Path::new("benchmarks/data/pizza.owl"))?;

Or run cargo run -p ontologos-core --example pizza_builder.

Where is the API reference?

Does pip install ontologos work?

The PyPI package is an alpha release (v0.5.0). It supports profile="auto", "el", "rl", and "rdfs":

Reasoner("ontology.owl", profile="rdfs").classify()  # RDFS materialization
Reasoner("ontology.owl", profile="rl").classify()    # OWL RL saturation

See Python guide for the full API and limitations.

Where do I ask questions?

Open a GitHub issue for bugs, feature requests, or design questions. Check this FAQ and Troubleshooting first.